Rita watched aghast as Roddy vanished.

"I'll be back to help as soon as I can, Dad!" she promised quickly before taking off after her companion, leaving her father and the others slightly bemused.

"Roddy! Where do you think you're going?"

Roddy paused as he boarded the Jammy Dodger II. Rita vaulted the rail and landed next to him, glaring.

"I was…just going to get my things ready," he invented, desperately.

"You were trying to leave without me!"

"No I wasn't! I was…" He floundered.

"Trying to leave without me?" suggested Rita, tapping her foot. Roddy gave up. Rita's tail was flicking from side to side as well, and under those circumstances it was safer and easier to yield painlessly.

"All right, you caught me. I'm sorry. You just seemed to be busy with your father and I thought I might be able to make a start."

"Why would you try to leave by yourself? You might not be able to make it alone." Rita watched him, nervousness overcoming her initial anger.

"Well, it was because…it was because…" Roddy trailed off. It was because having you there will make this harder than it already is! But he couldn't bring himself to say it. He stood there in silence until Rita took pity on him.

"Prepare to cast off, then," she said. "We'll have to get going."

They prepared the boat in silence. As the engine fired up and Rita began reversing into the tunnel, her father came bowling through the hole in the gate, waving his hands frantically.

"Wait! Wait! I've got something important to tell you!"

Rita cut the engine and gunned the reverse thrusters hard, throwing Roddy off-balance.

"What is it, Dad?" she called. Sid clambered through the gate and joined Mr Malone.

"Wait! Wait! I've got something important to tell you!"

"I've already done that part, Sid," said Mr Malone. "But thanks for helping. Rita, didn't you notice that the city was empty?"

"Yes?"

"Didn't that strike you as odd?" said Mr Malone.

"Well, we assumed it was because it was Christmas Eve," said Roddy.

"No such luck!" shouted Sid. "Think about it, Rita! With this place out of commission-" he jerked his thumb at the plant behind him- "all the currents that stop boats from getting Up Top will be gone!"

Rita stared as she worked it out. "Everyone's gone Up Top for Christmas?"

"Everyone with a boat or a will to swim!" shouted Mr Malone. "The humans are going six kinds of bonkers! They think it's a plague!"

Roddy joined Rita at the helm. "That could make things difficult," he said.

"The City's called in ratcatchers!" yelled Sid. "They're trying to hunt everything with a tail!"

"Do you want to turn back?" said Roddy to Rita. "This isn't your problem. If you want to stay-"

"Where you go, I go," said Rita, taking his hand below the cockpit wall. She waved back to Sid and her father. "Thanks for the warning! Good luck with the salvage!" She opened the throttle and the engine drowned out her father's objections.

Roddy looked at the maps as they motored back into the main drains.

"It's a lot different from last time. We never actually worked out how to get back to my place…I mean, my old place, by boat. We ended up arriving by air mail."

"Maybe we should have asked Jasper to fly us," said Rita.

"No, I think arriving is the important part."

"What happened to the journey being the best bit?" Rita smiled.

"People who say that have never flown Air Jasper," said Roddy. "Look, Rita, really. You don't have to risk coming with me. If there's ratcatchers up there we could end up in great danger."

"Oh, yeah. Because that's never happened to us before," said Rita, rolling her eyes jokingly. "Not another word on the matter Roddy. Or I'll throw you overboard and go to Kensington myself."

The Flying Malone was indeed in an outfall drain near the park lake and it had indeed been modified. The Lancaster's four mighty engines had been rebuilt into two nacelles closer to the main fuselage, one propeller facing astern and one forward on each wing in push-me-pull-you style. This had allowed the immense wings to be fitted with hinges, which enabled them to be folded up and over the fuselage and thus making the seaplane narrow enough to fit into the pipe- barely.

"At some point they're just going to end up replacing the whole thing," said Roddy, looking at it. Rita, whose eyes were more mechanically aware, noticed something more interesting. Part of the Lancaster's underbelly had been removed and was replaced with a dull gunmetal cylinder. The dorsal fuselage over that part had also been modified- it was still RAF black-and-tan coloured but it was hinged as if concealing something.

"I wonder what that could be?" she said speculatively.

"Whatever it is, I want to be a long way away when they switch it on," said Roddy firmly.

Rita crossed her arms. "You could show a little more trust in Jasper's engineering. He saved your tail on Burhou, remember?"

"You mean over Burhou, when he very nearly took it off, right?" said Roddy, remembering his midair confrontation with the Toad. "And for the record, it isn't Jasper I don't trust, it's Bruce."

"Which Bruce?"

"Any Bruce."

They turned into the current again and sailed out onto the Kensington Gardens lake. Patchy clouds obscured a pale winter sun. Rita shaded her eyes with her hand as she gauged the wind.

"Are you sure we can get to your place from here?"

"We need to cross the lake," said Roddy. "This is the quickest way. Why do you ask?"

"Because it's daylight and anybody looking at the lake can see us." Rita had survived as long as she had by knowing that discretion was often the better part of not being killed. She didn't like being in the open.

"I don't think the ratcatchers will have snipers on the rooftops," said Roddy.

"I'm not worried about the ratcatchers," said Rita. She pointed to something out on the lake. Roddy followed her finger. At first he thought it was another boat, a large white one- and then the 'boat' raised an enormous head and regarded them with a suspicious yellow eye.

"It's a pelican!" he said. "I didn't think they'd still be here in winter!"

"Exhibit-A there should answer that," said Rita. "That thing looks like it could swallow this whole boat in one go. Look at that beak!"

Roddy was trying not to. "Well, it'll have a nasty surprise if it does," he said.

"I don't want to think about what it could do before realising that," said Rita meaningfully. "Are you sure this is the safest way?"

"I didn't say it was the safest way, I said it was the quickest." Roddy sat down and watched the pelican, which had gone back to ignoring them with majestic distain.

"That's a distinction you need to pay more attention to," said Rita. "Keep an eye on the featherbed over there. If it so much as twitches in our direction, I'm getting us out of here."

Roddy nodded and kept an eye on the pelican, which had turned away and was investigating something over by the bank.

"See? There's no danger there." He sat back and turned to the maps again.

A shadow passed overhead. Roddy looked up and swallowed nervously.

"Up there, on the other hand…there might be some danger…"

Rita looked up and cursed.

"Two pelicans! How can there be two?"

"Apparently quite easily!" said Roddy. The second pelican turned gracefully and came in for landing. It touched down just ahead of the Jammy Dodger II and regarded the approaching boat with the kind of stupidity that only birds can muster. The great bird's landing had thrown up a powerful ripple in the water, and the Dodger bucked violently. Roddy was thrown out of his chair and banged his nose against the control panel, activating the mechanical arm which shot out of its silo and punched the pelican square in the face. It sat there for a moment, cross-eyed, and trying to figure out what had just happened. Pelicans think slowly, but its instincts told it that sitting around in an environment that threw punches like that was not a good idea. It took off hurriedly, splattering the Jammy Dodger II with water.

"Good work!" said Rita appreciatively. "I think you took it by surprise!"

"It's not the only one," said Roddy, rubbing his nose tenderly. He stood up and looked around. Maybe they'd get away with the lake crossing anyway! Then he realised that he'd lost sight of the first pelican.

"Um, Rita?"

The sun was blocked out and the boat was almost swamped by a sudden wave. Rita was thrown sideways into Roddy and the pair slammed into the side of the cockpit. Rita scrambled to her feet and stared into the mad yellow eyes of the first pelican, which had just landed beside them. It opened its beak and water rushed into the cavern. Rita felt the boat begin sliding into the flow and she made a lunge for the controls. The engines roared as she slammed the throttle wide open and the pelican swallowed a mouthful of water and exhaust fumes.

"Eat that!" she shouted ecstatically. "You came and had a go, but you weren't fast enough! Hahaha!"

Roddy, who had been thrown back on to the main deck by the sharp acceleration, got to his feet and joined her triumphant laugh.

That was when the second pelican swooped low over the deck and grabbed him in its webbed feet. He was borne skywards as the great white and black bird flapped furiously.

"This can't be happening twice!" he shouted in frustration, flailing at it.

Rita gasped and brought the mechanical arm around as fast as she could. It grabbed onto Roddy's foot just as the pelican tried to carry him beyond her reach. The bird was still strong, however, and it began dragging the Jammy Dodger II along behind it as it fought for height.

"This isn't very comfortable, Rita!" shouted Roddy, who was caught between the boat and the bird.

Rita looked around desperately and threw the engines into full reverse. The sudden yank made Roddy cry out in pain, but it brought the pelican crashing back to the lake with a splash that soaked Rita to the skin. Roddy surfaced, spluttering, still in the grip of the mechanical arm.

"Hold on, Roddy!" Rita swung the arm around and dropped him back on board. She activated the boat's thrusters again and executed the nautical equivalent of a handbrake turn before accelerating forward, steering them back towards the Flying Malone's outfall. Behind her, a second splash indicated the second pelican had tried a dive attack and come to watery grief.

Rita brought them to a stop as soon as they were safely inside the drain. Her wake made the Flying Malone bob sharply and the folded wings banged off the drain roof. Breathing a sigh of relief, she turned back to Roddy who was lying in the stern.

"Are you all right?" she asked, still breathing hard.

"Give me a moment…I'm…pretty sure I'm all here." Roddy patted himself to check that everything was still attached. "That sort of thing shouldn't happen to a chap twice…there should be a law."

"Well, you were complaining about how Jasper rescued you the last time that happened," said Rita, helping him up. "So I thought I'd show you how I do things."

"I'm starting to regret what I said about Jasper," said Roddy ruefully. "Is it just me or am I a little bit taller? I feel like a spaghetti noodle."

"This is hardly the time to get hungry," said Rita, severely.

"No, I mean I feel like a spaghetti noodle." Roddy arched his back and winced. "Thank you, by the way. For saving me. Again."

"Make sure it doesn't happen again, that's all I ask," said Rita, putting on a façade of bravado to cover up the anxiety she had felt. That had come too close for comfort. "I guess we'll have to find another way back to your street. Get the maps out and we'll see where the drains lead."

Mr Malone peered over the edge of the salvage platform, which he had put together out of icy pole sticks and staples. Steel cables were tied to each corner, meeting in the air above the centre of the platform before running up to the crane.

"Water level's gone down a bit, hasn't it?" he said.

Bruce One nodded. "It has, that. And look, it's still dropping." He pointed to the water level, which was falling away as the Hyde Park Treatment Plant drained itself. Bruce Two dropped a lead and line over the edge.

"Six feet left!" he shouted. Not long now!"

Mr Malone looked up and cupped his hands around his mouth.

"Did you hear that, Jasper? Sid?" he called.

"Six feet it is sah!" said Sid, who was sitting at the crane's controls being supervised closely by Jasper. The old mechanic was buffing the control panel with a piece of sponge.

Mr Malone looked down again and realised that the platform was tipping alarmingly beneath him. He looked to his left and saw the Bruces had joined him.

"Get back, will you? You'll overbalance us and we'll all go in!" He waved them back. They retreated to the centre.

"What's the problem, mate? I thought the water was cool now." Bruce One asked.

"It is, but the chemical content will still be high enough to turn you white!" said Mr Malone, pointing to the water.

"It's that frightening?" said Bruce Two, curiously, peering through a gap in the platform boards.

Mr Malone sighed. "I mean it'll literally turn you white. That's not stuff you play around with under any circumstances. You know what Jasper always says about safety?"

"Safety first," intoned the Bruces, in despairing unison.

"That's right," said Mr Malone. "And I say it too." He nodded to them pointedly and looked over the side. Shapes were emerging from the water, dripping. A frisson of excitement ran through Mr Malone's body as he recognised a mechanical hand, frozen forever in a permanent wave.

"Jammy? Is that you?" he whispered, almost overcome with feeling for his old boat.

"No, it's Bruce," said Bruce Number One.

"I'm talking to the boat!" snapped Mr Malone.

"Because that makes perfect sense," said Bruce Number Two.

"There's nothing you can do about them!" called down Jasper. "They're chronic! I told you about them!"

The Bruces looked up. "No need for that, mate! Fair go!"

A piece of wet sponge dropped from the crane platform and hit Bruce One in the face with a splatter.

"Sorry!" called Jasper happily. "Lost my grip there for a moment!"
"He's lost his grip all right," muttered Bruce One, wiping his eyes.

"What happened to safety first?" shouted Bruce Two.

"There's an exception to every rule!" replied Jasper.

Muttering various imprecations, the Bruces went to opposite sides of the salvage platform and looked down as the last of the water drained away. The bottom of the treatment plant was strewn with debris carried in by the drains, but most of it had been hard-boiled into a pulpy mess of unrecognisable constituency. Only one thing was clearly identifiable- a boat, or what once had been. Months immersed in boiling, chlorinated water had not done it much good. Every surface was a bleached white as if all the colour had been sucked from it, but there was no mistaking the name on the stern.

"It's the Jammy Dodger," said Mr Malone, tears in his eyes. "Lads, if you knew half of what I've been through in that tub. Me and Rita…all those years of prospecting…" He smiled and shook his head to clear the memory. He called up to Sid again.

"Move us over a bit! Two points left!"

The platform jerked away from the derelict ship and Bruce One was forced to make a grab for his companion's feet as he fell over the edge.

"The other left, mate! The other left!" he screamed.

Sid scratched his head. "Do you mean stage left or what?" he said.

Jasper heaved a sigh and reached past him for the controls. The platform moved and positioned itself over the Dodger's after deck.

"Down a bit!" called Mr Malone.

The platform rose fractionally, and then plunged down with a clatter of wood. It crunched into the battered tyre at the back of the wrecked boat and tipped sideways, spilling its three passengers onto the white-bleached deck.

"Down a bit," muttered Bruce Two, getting to his feet. "Down like a lead balloon, more like."

Bruce One rolled out from under the platform and moaned. Mr Malone stood up, rubbing his elbow and looked around.

"We're on board! We're on board Jasper!" he shouted.

"Good show!" The reply floated down.

The Bruces stood up and joined Mr Malone, who was beaming from ear to ear.

"Now what do we do, mate?" asked Number One.

Mr Malone touched a railing fondly. "We'll have to check her out. Make sure she's still in one piece. Then we'll figure out a way to get her attached to the crane so we can bring her out."

"No worries," said Bruce the First. "I'll check out the engine, shall I?"

Mr Malone shook his head. "No, we should check the hull first. Engines are nice but you've got to float to use 'em. This isn't a submarine, lads."

"Contrary to appearances," said Bruce Two, innocently. Mr Malone ignored the remark.

"I wish Rita was here to see it. And I'm pretty sure young Roddy would like to see it as well."

"I think they're seeing enough of each other," said Bruce One, who was assessing the hull's integrity by kicking it repeatedly.

"Oh, I hope so. They're so good together," said Mr Malone. "Reminds me of me and the wife when we was their age. Anyway, enough of that. I'm sure they'll be fine."

"Speaking of the wife," said Bruce. "It's Christmas Day now. Shouldn't you be getting back to the family?"

Mr Malone shook his head. "They know I'm here. There's no telling when we'll have the opportunity to finish the salvage."

"Jasper's here too," pointed out Bruce Two.

"If that's an advantage," said Bruce One, before ducking under the cover of the Jammy Dodger's roof.

"And Sid's on the crane," went on Bruce Two.

"I'm staying," said Mr Malone firmly. "We're going to finish this today. We may not get another chance."

Rita looked up at the grate. One of its bars had rusted through, opening up a rat-sized hole. She stopped the Jammy Dodger II underneath it and telescoped the mechanical arm up to it as a ladder.

"This is as close as we get," she said to Roddy. "If your maps are right we should be just a street or two away."

Roddy looked up and shaded his eyes from the daylight. "Is it safe to leave the boat here?" he asked.

"Safer than the lake," said Rita.

"A nuclear testing range would be safer than the lake," said Roddy, shivering and wringing out his sleeve. "Sorry about that. I shouldn't have plotted the course across it."

"It was worth trying, Roddy," said Rita comfortingly. "Sometimes, in life, you have to take a chance."

Roddy nodded. "Well…do you want to take this one together?"

"Always."

They scrambled up the arm and through the grate. They were on the edge of a road and had to dart across the footpath into the cover of a hedge. Roddy peered out and tried to work out where he was.

"Okay, we are quite close," he said. "It's only a couple of houses away. My mapreading must be better than even I thought!"

Rita snorted.

"I'll pretend that didn't happen," said Roddy. "Let's go. And stay low."

"You're telling me how to move stealthily?" said Rita, amused. She set off after him.

Ducking and weaving between the shelter of the hedge and the gutter, they made their way down the street until Roddy recognised his old house number. A small plastic Christmas tree glowed in the window and a wreath hung on the door, resplendent in green, red and gold.

"This is it," he said quietly. Rita joined him.

"Now we've just got to get inside," she said. "I guess the front door's not an option?"

Roddy pointed to an air duct just below the footpath level. "We can get in through there. I found that ages ago. It was a useful way in and out."

"You went out?" Rita was surprised. It was hard for her to imagine anyone leaving the luxurious flat.

"Not really, but it would have been useful if I did." Roddy heaved the grate aside and stepped into the duct. Rita followed. It came out under the house, a wide, low wooden-roofed space broken up by foundation pillars, floor joists and the pipes and wires carrying water and power to the flat. Roddy walked along in silence, counting the pillars, until he paused under one.

"This is it," he said. "This is under the old room where I used to live." He looked up at the cobweb-dusted plank and drew a deep breath.

"Do you want me to come with you?" Rita put her hands on his shoulders and was stunned at how tense he was. She flexed her fingers, trying to relax him. Roddy closed his eyes and fought down the temptation to let her continue. This was exactly why he had tried to give her the slip- her presence would only confuse him further and he felt guilty for knowing it.

"No. No, I'm sorry. This last bit…this last bit has to be mine." He stepped away from her and opened an access hatch in the central heating duct. Roddy ducked inside, and was gone.

Rita watched him go and sighed. Whatever happened now, it was Roddy's decision. Coming back to Kensington had been as dangerous as it had been the first time, but she couldn't help feeling that the critical part was yet to come. She brushed aside some cobwebs and sat down on a half-buried brick to take in her surroundings. Then she noticed that there were some new-looking objects down here- little cardboard cylinders had been placed between the floor joists on either side of her. They were all connected with what looked like string, which disappeared out into the back garden.

Rita looked at them curiously, and wondered what they were.